Field of the Invention
The present invention relates to a light source unit and a projector including this light source unit.
Description of the Related Art
In these days, data projectors are used on many occasions as an image projection system which projects a screen of a personal computer and a video image, as well as images based on image data which is stored on a memory card on to a screen. These projectors are such that light emitted from a light source is collected on to a micromirror display device which is called a DMD (Digital Micromirror Device) or a liquid crystal panel so that a collar image is displayed on the screen.
In recent years, for those projectors, there have been developed and proposed various light source units which use a plurality of semiconductor light emitting devices such as laser diodes as a light source and which include a plurality of optical members such as lenses and mirrors in association with the use of such semiconductor light emitting devices.
For example, a light source unit is proposed which includes an excitation light source which emits light in a range of blue wavelengths by the use of a laser diode and an optical wheel (a rotary plate) which has a luminescent material layer which absorbs light emitted from the excitation light source to convert it into visible light and which is driven to rotate by a motor, and a projector including this light source is proposed.
Then, as disclosed in Japanese Unexamined Patent Application No. 2013-097233 (JP-A-2013-097233), the applicant of this patent application has proposed and implemented the projector including the excitation light shining device having the blue laser diodes. This projector includes the light source unit in which excitation light from the excitation light shining device is shone on to the rotating luminescent wheel, light in the range of green wavelength range is emitted from the luminescent material layer of the luminescent wheel, the diffuse transmission portion is formed on part of the luminescent wheel so that the excitation light which is light in the range of blue wavelengths is transmitted therethrough, and light in the range of red wavelengths which is emitted from the light emitting diode is combined with the light in the range of green wavelengths and the light in the range of blue wavelengths so as to be emitted altogether in the same direction.
Additionally, as represented by the projector disclosed in Japanese Unexamined Patent Application No. 2003-287815 (JP-A-2003-287815), the projector has been disclosed and proposed in which light source light of the high-pressure discharge lamp which emits white light is separated into red light, green light and blue light by the dichroic mirror, the red light, the green light and the blue light are made into the three primary image lights by the liquid crystal panel which is the optical modulator, and thereafter, the three primary image lights are combined together by the dichroic prism for projection.
As described above, in the projector, many lenses and mirrors are used in the optical systems including the light source unit which are incorporated in the projector. In order to enhance the brightness of a projected image and the color repeatability, the optical members such as lenses and mirrors are assembled together with great care so as not only to dispose the lenses in the predetermined positions but also to set the center axes (optical axes) of the lenses in the predetermined positions.
In addition, as described above, in the optical systems of the projector, although the lenses and mirrors are assembled together while installing them in the predetermined positions with high accuracy, it is difficult to fix the lenses and mirrors in the predetermined positions with high accuracy due to the finishing tolerances of the lenses and mirrors themselves and the production tolerances of the constituent parts into which the lenses and mirrors are incorporated. However, the highly accurate mounting is attempted to be realized through the secondary cutting or by using the secondary fixing parts in part of the assembling work, and this requires a lot of trouble and a large number of labor hours.